A mobile device user is often a subscriber to a wide area network owned and operated by a given network operator or carrier that owns the associated network infrastructure. The wide area network serves as a “home network” for the mobile device. Mobile devices that move outside of the coverage area of their respective home networks often utilize roaming services that enable a mobile device to connect to various public land mobile networks (PLMNs) which are wireless wide area networks (WANs) that provide mobile device service for a given geographic location. Some geographic locations may be served by more than one PLMN such that a mobile device user may have a choice as to which PLMN is preferable. In most cases, a mobile device is subscribed to a single PLMN, and that PLMN determines which other PLMNs are “preferred” for its customer mobile devices based on contractual arrangements existing between these PLMN entities. In other business models, a mobile virtual network operator (MVNO) may provide mobile devices with services using various PLMNs, where the MVNO entity contractually purchases or leases access to network resources on the various PLMNs without owning any of the network infrastructure. A mobile device may access a PLMN, either automatically or manually, by selecting it from a preferred roaming list (PRL) stored within the mobile device such as in memory or on a subscriber identity module (SIM) card. A mobile device may obtain a PRL from its subscribed PLMN (i.e. home network), or from an MVNO, and may scan for available PRL PLMNs in the location of the mobile device when the mobile device is roaming (i.e. when outside of the home network coverage area), anytime that coverage from the home PLMN is lost, or when the mobile device is powered on. A mobile device using an MVNO business model must also conduct scanning at various times such as when the mobile device is powered on, etc.
One issue that arises when scanning to find PRL networks in a multi-radio networking scenario is that, the mobile device will attempt to scan for all the bands because some of the “preferred” PLMNs may not be found. Such complete scans can take as much as 12 minutes and can cause extensive battery drain with no resulting service to the end-user. In addition, even when a PRL is available for a wireless service provider, who own multiple bands and multiple radio frequencies (such as, but not limited to, an MVNO), overhead is involved in finding a suitable PLMN on which to “camp.” This complexity is further increased for a global roamer who moves between countries where wireless network providers utilize a multiplicity of bands and frequencies.